Linked Life Data

15138266

Source:http://linkedlifedata.com/resource/pubmed/id/15138266

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
29
pubmed:dateCreated
2004-7-12
pubmed:abstractText
Tumor necrosis factor-alpha (TNF-alpha) inhibits osteoblast function in vitro by inhibiting collagen deposition. Studies generally support that TNF-alpha does not inhibit collagen biosynthesis by osteoblasts but that collagen deposition is in some way diminished. The study investigated TNF-alpha regulation of biosynthetic enzymes and proteins crucial for posttranslational extracellular collagen maturation in osteoblasts including procollagen C-proteinases, procollagen C-proteinase enhancer, and lysyl oxidase. The working hypothesis is that such regulation could inhibit collagen deposition by osteoblasts. We report that in phenotypically normal MC3T3-E1 osteoblasts, TNF-alpha decreases collagen deposition without decreasing collagen mRNA levels or procollagen protein synthesis. Analyses of the cell layers revealed that TNF-alpha diminished the levels of mature collagen cross-links, pyridinoline and deoxypyridinoline. Further analyses revealed that the mRNA expression for lysyl oxidase, the determining enzyme required for collagen cross-linking, is down-regulated by TNF-alpha in a concentration- and time-dependent manner by up to 50%. The decrease was accompanied by a significant reduction of lysyl oxidase protein levels and enzyme activity. By contrast, Northern and Western blotting studies revealed that procollagen C-proteinases bone morphogenic protein-1 and mammalians Tolloid and procollagen C-proteinase enhancer were expressed in MC3T3-E1 cells and not down-regulated. The data together demonstrate that TNF-alpha does not inhibit collagen synthesis but does inhibit the expression and activity of lysyl oxidase in osteoblasts, thereby contributing to perturbed collagen cross-linking and accumulation. These studies identify a novel mechanism in which proinflammatory cytokine modulation of an extracellular biosynthetic enzyme plays a determining role in the control of collagen accumulation by osteoblasts.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
30060-5
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Regulation of collagen deposition and lysyl oxidase by tumor necrosis factor-alpha in osteoblasts.
pubmed:affiliation
Department of Oral Biology, Goldman School of Dental Medicine, Boston University, Boston, Massachussetts 02118, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't